Talking to yourself may seem a little shameful. If you've ever been overheard berating yourself for a foolish mistake or practicing a tricky speech ahead of time you'll have felt the social injunction against communing with yourself in words. In the well-known saying, talking to yourself is the first sign of madness.
But there's no need for embarrassment. Talking to ourselves, whether out loud or silently in our heads, is a valuable tool for thought. Far from being a sign of insanity, self-talk allows us to plan what we are going to do, manage our activities, regulate our emotions and even create a narrative of our experience.
Take a trip to any preschool and watch a small child playing with her toys. You are very likely to hear her talking to herself: offering herself directions and giving voice to her frustrations. Psychologists refer to this as private speech: language that is spoken out loud but directed at the self. We do a lot of it when we are young — perhaps one reason for our shyness about continuing with it as adults.
As children, according to the Russian psychologist Lev Vygotsky, we use private speech to regulate our actions in the same way that we use public speech to control the behavior of others. ("I'm hungry, can you bring me something to eat?" versus "I'm hungry, I should get myself something to eat.") As we grow older, we don't abandon this system — we internalize it.
Imagine being able to tune in to the thoughts of the person next to you: in the office, on the bus, walking in the park. Much of what you would overhear would take the form of language. "Pick up some coffee." "Remember to phone the plumber." Many people say that they have a little voice up there, guiding them, helping them to think through problems and sometimes chastising them for their mistakes.
Psychological experiments have shown that this so-called inner speech can improve our performance on tasks ranging from judging what other people are thinking to sorting images into categories. The distancing effect of our words can give us a valuable perspective on our actions. One recent study suggested that self-talk is most effective when we address ourselves in the second person: as "you" rather than "I."
With new neuroscientific techniques, we can even explore what's happening in the brain when inner speech is going on. Mental dialogues draw on some of the same neural systems that underpin the conversations we have out loud and might explain the more unusual experience of "hearing voices" (or auditory hallucinations). We know that inner speech comes in different forms and speaks in different tongues, that it has an accent and emotional tone, and that its special properties mean it can unfold more quickly than speech said aloud.
I said that we internalize the private speech we use as children — but we never entirely put away the out-loud version. If you want proof, turn on the sports channel. You're bound to see an athlete or two gearing himself up with a tart phrase or scolding herself after a bad shot. Andy Murray attributed his 2012 U.S. Open victory to a pep talk he gave himself in front of a changing-room mirror. Gymnastics star Laurie Hernandez was caught on camera telling herself "I got this" before a key event in Rio. The athletes are doing it for good reason: Self-talk has been shown to bring benefits in sports as diverse as badminton, darts and wrestling.
Those of us who lack the talent of a Hernandez or a Murray are also likely to talk to ourselves aloud, particularly when the task is difficult and the conditions stressful. Researchers have observed high levels of private speech when adults are immersed in attention-demanding tasks like data entry — although, poignantly, many participants deny having talked to themselves when quizzed afterward. That social pressure not to think out loud is very real.
Conducting a dialogue with ourselves — asking questions of the self and providing answers — seems to be a particularly good way of solving problems and working through ideas. The to-and-fro between different points of view means our thoughts can end up in expected places, just like a regular dialogue can, and might turn out to be one of the keys to human creativity.
Both kinds of self-talk — the silent and the vocal — seem to bring a range of benefits to our thinking. Those words to the self, spoken silently or aloud, are so much more than idle chatter.
Charles Fernyhough is the author, most recently, of "The Voices Within: The History and Science of How We Talk to Ourselves."